Wireless network, including wireless metropolitan area networks (WMAN) such as those compliant with the IEEE standard 802.16.x (WiMAX), may communicate using Orthogonal Frequency Division Multiplexing (OFDM) signaling. An OFDM signal is comprised of multiple sub-carriers each modulated at a symbol rate equal to the reciprocal of the frequency separation. WiMAX networks may assign neighboring base stations different preambles. The preambles are included as the first OFDM signal in a WiMAX frame and may be selected from a set of 114 symbols. The preamble symbols from different base stations may use the same frequencies and therefore interfere with each other, causing negative signal to noise ratio (SNR) at cell edge.
During signal acquisition with a particular base station a WiMAX OFDM receiver in the wireless device does not know what preamble is associated with the base station, or the frequency or timing offsets associated with the signals. As a result, preamble detection needs to account for uncertainties in preamble, frequency and time at a SNR below zero. Searching for all unknowns at the same time may result in high error rate.